1. Field
Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to a method and apparatus for generating 40+40 MHz and 40+40+40+40 MHz transmission modes for IEEE 802.11 wireless communications systems using IEEE 802.11ac waveforms with application to IEEE 802.11af wireless communication standard.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Examples of such multiple-access networks include Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.
In order to address the issue of increasing bandwidth requirements that are demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs. Multiple Input Multiple Output (MIMO) technology represents one such approach that has recently emerged as a popular technique for the next generation communication systems. MIMO technology has been adopted in several emerging wireless communications standards such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. The IEEE 802.11 denotes a set of Wireless Local Area Network (WLAN) air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters).
The IEEE 802.11 WLAN standards body established specifications for transmissions based on the very high throughput (VHT) approach using a carrier frequency of 5 GHz (i.e., the IEEE 802.11ac specification) targeting aggregate throughputs larger than 1 Gigabits per second. One of the enabling technologies for the VHT 5 GHz specification is a wider channel bandwidth, which bonds two 40 MHz channels for 80 MHz bandwidth therefore doubling the physical layer (PHY) data rate with negligible increase in cost compared to the IEEE 802.11n standard.
A scheme known as “white-fi” entails expanding Wi-Fi technology with the unused frequency spectrum in the television (TV) band (i.e., the TV white space). An Institute of Electrical and Electronics Engineers (IEEE) 802.11af task group has been created to define an amendment to the IEEE 802.11 standard for using the TV white space (TVWS). The IEEE 802.11 denotes a set of WLAN air interface standards developed by the IEEE 802.11 committee for short-range communications (e.g., tens of meters to a few hundred meters). However, by using the TVWS with frequencies below 1 GHz, IEEE 802.11af may offer greater propagation distances to be achieved, in addition to the increased bandwidth offered by the unused frequencies in the TV spectrum.